Screws: Number Of Turns Engagement For Full Strength?

M5, .80 pitch screw connects into a barrel-shaped piece.

Full engagement is 7 or 8 turns.

Anybody know how many turns are required for full strength?
(i.e. how far can I back it out without risk?).
--
PeteCresswell

(PeteCresswell) wrote:
M5, .80 pitch screw connects into a barrel-shaped piece.

Full engagement is 7 or 8 turns.

Anybody know how many turns are required for full strength?
(i.e. how far can I back it out without risk?).

need more info - barrel-shaped piece of /what/? in what application?

PeteCresswell wrote:

M5, .80 pitch screw connects into a barrel-shaped piece.

Full engagement is 7 or 8 turns.

Anybody know how many turns are required for full strength?

Full axial load on a fastener can be carried by three threads,
usually. But the three threads on the tip of a screw are not usually
uniform enough to be the three that can do this. Throw any bending
load into the mix, even small, and you'll need more threads engaged,
just so that your critical three don't get damaged as you torque the
fastener. (Sounds like the "barrel shaped piece" is a special nut
designed to keep excessive bending loads off of the screw in a pinch
clamp application. Friction between barrel and bore will still leave
you with some bending load on the screw, so grease the cylindrical
surface if you can.)

(i.e. how far can I back it out without risk?).

I'd look for 5 threads of engagement. Better yet, I'd look for a
longer screw. M5x0.8 isn't exactly rare or difficult to find. Is it
a special spherical-headed screw or something?

Chalo

Jambo wrote:
"jim beam" wrote in message
t...
need more info - barrel-shaped piece of /what/? in what application?

As if you'd know, ****tard.

oh dear, mr. modulus is back. won any boeing materials contracts lately?

"jim beam" wrote
need more info - barrel-shaped piece of /what/? in what application?

Jambo wrote:
As if you'd know, ****tard.

Without regard to the merits I have never seen nor heard that word
outside r.b.t.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Per Chalo:
I'd look for 5 threads of engagement. Better yet, I'd look for a
longer screw. M5x0.8 isn't exactly rare or difficult to find. Is it
a special spherical-headed screw or something?

Nothing special. M5x0.8 socket head @50mm.

Definitely gonna go the right-length route.

Tried the local hardware... then tried Lowe's...

Was about to turn off to try Home Depot and a little voice
whispered "You dummy!!!! This is a textbook case for buying via
somebody's web page."

Prolly dropped 2 man hours and 50 vehicle miles into it.

--
PeteCresswell

On Sat, 08 Sep 2007 13:42:59 -0500, A Muzi
wrote:

"jim beam" wrote
need more info - barrel-shaped piece of /what/? in what application?

Jambo wrote:
As if you'd know, ****tard.

Without regard to the merits I have never seen nor heard that word
outside r.b.t.

Dear Andrew,

I had not suspected that a local bike shop owner might lead a life
even more sheltered than mine:

http://www.google.com/search?as_q=fu...s=&safe=images

In contrast to such tiresome snarling, the most original vituperation
that I've seen lately was in Susan Wenger's parody of O'Brian's
Aubrey-Maturin Royal Navy novels, where Wenger out-did O'Brian's
frequently masterful insults ("Incest is nothing to them!") in a
passage exaggerating O'Brian's stock scene about the foul sailor's
language picked up by Captain Aubrey's innocent little twin daughters:

"Mama," screeched Carlotta, her wet hair streaming down her chubby
cheeks, "That goddamned bosun's hemorrhoid Fancy has took my goddamned
toy boat!"

--"The Port-Wine Sea," p. 39

For more delicate souls, Wenger includes several puns so awful that
even O'Brian dared not put them in Aubrey's mouth.

Cheers,

Carl Fogel

PeteCresswell wrote:

Was about to turn off to try Home Depot and a little voice
whispered "You dummy!!!! This is a textbook case for buying via
somebody's web page."

Prolly dropped 2 man hours and 50 vehicle miles into it.

When all else fails, or if you just can't be bothered to look in more
than one place:

http://www.mcmaster.com

Chalo

Per Chalo:
When all else fails, or if you just can't be bothered to look in more
than one place:

http://www.mcmaster.com

Wow!.... Now *that*s a search utility.

Made my 'keepers' list.

Thanks.
--
PeteCresswell

Per Chalo:
http://www.mcmaster.com

Also - now I know what .80 pitch means.
--
PeteCresswell